A substrate treating apparatus includes an indexer, a processor, and an interface. The indexer takes a substrate from a carrier accommodating a plurality of substrates to the processor, and accommodates the substrate from the processor to the carrier. The processor performs treatment such as a resist coating, a developing process, and a heat treatment. Then the interface delivers and receives the substrate to and from an external exposing machine.
The exposing machine is disposed adjacent to the interface of the substrate treating apparatus. The exposing machine adopts an exposure technique with an immersion method (hereinunder, referred to as an “immersion exposure technique”) for achieving more minute exposure patterns in recent years. In the immersion method, a liquid is charged between a projection optical system of an exposing machine and a substrate for exposure. However, in the immersion exposure technique, the exposure is performed with the substrate contacting the liquid. Accordingly, the substrate is transported from the exposing machine with the liquid (immersion liquid) adheres on the substrate subjected to the exposure. Consequently, the liquid adhering on the substrate transported from the exposing machine drops off within the substrate treating apparatus. This may cause operation failure of the substrate treating apparatus or a decreased degree of cleanness in the substrate treating apparatus.
Then, Japanese Unexamined Patent Publications No. 2008-028226A and 2009-071026A each suggest the feature that a cleaning/drying unit is disposed within the interface for performing cleaning and drying treatments to a substrate to remove a liquid adhering on the substrate. Moreover, Japanese Unexamined Patent Publication No. 2012-222237A discloses a treating method of cleaning and drying a substrate, provided that this publication has no disclosure about the use of the method for the purpose mentioned above. The substrate treating methods as mentioned above are to be described in turn.
The following describes the substrate treating method in Japanese Patent Publication No. 2008-028226A. A substrate W held on and rotated by a spin chuck is cleaned with a cleaning liquid, and the cleaning liquid is rinsed off with the rinse liquid. Then, a rinse liquid layer (puddle) L is formed on an entire surface of the substrate W. Then, the rinse liquid stops discharging, and the nozzle (liquid supply nozzle) is brought into retraction. Then, a rotation speed of the substrate W is increased, whereby the substrate W becomes thick at a periphery edge of the substrate W and becomes thin at the center of the substrate W (see FIG. 1A). At this time, the center and the periphery of the liquid layer L are under a tensioned state.
Then, an inactive gas supply nozzle 284 is moved above the center of the substrate W, and discharges inactive gas to a portion of the liquid layer L with a small thickness, whereby a hole H is formed at the center of the substrate W (see FIG. 1B). This eliminates the tensioned state, and the liquid layer L is integrally moved toward outside of the substrate W by a centrifugal force with a kept ring boundary between the hole H and the liquid layer L (see FIG. 1C). Consequently, the substrate W can be dried with retrained formation of minute droplets of the layered rinse liquid on the substrate W.
The following describes the substrate treating method in Japanese Unexamined Patent Publication No. 2009-071026A. A substrate W held on and rotated by a spin chuck is cleaned with a cleaning liquid, and the cleaning liquid is rinsed with a rinse liquid. Then, a rotation speed of the substrate W is increased while a nozzle 283 above the center of the substrate W discharges the rinse liquid to form a liquid layer L of the rinse liquid on an entire surface of the substrate W (see FIG. 2A). Then, the nozzle 283 is moved outwardly from above the center of the substrate W. At this time, the thickness at the center of the liquid layer L is reduced by a centrifugal force caused by the rotation of the substrate W. Such a region having a small thickness is hereinafter referred to as a thin layer region.
The liquid supply nozzle 283 stops moving temporarily at the position spaced away from above the center of the substrate W by a given distance. In this time period, the liquid layer L is divided within the thin layer region by a centrifugal force, so that a hole (a drying core C) is formed at the center of the liquid layer L (see FIG. 2B). After the hole H is formed, the liquid supply nozzle 283 moves outward again. Correspondingly, a centrifugal force causes a dried region (hole H) where no rinse liquid exists to spread on the substrate W with the hole H as a starting point by (see FIG. 2C). Thereafter, the nozzle 283 stops discharging the rinse liquid when the nozzle 283 is moved to reach above the periphery of the substrate W. Then the nozzle 283 moves toward outside the substrate W. This causes the hole H to spread over the whole substrate W with the liquid layer L of the rinse liquid maintained uniformly, causing the substrate W to be dried while formation of the minute droplets is prevented.
The following describes the substrate treating method in Japanese Unexamined Patent Publication No. 2012-222237A. A substrate held on and rotated by a spin chuck (wafer holding and rotating unit) is processed with a cleaning liquid, and the cleaning liquid is rinsed with deionized water. Such rinse is performed by forming a liquid layer (liquid film) on an entire surface of a substrate. Thereafter, a rotation speed of the substrate is decreased, and a nozzle (outlet) above the center of the substrate supplies a low flow rate of deionized water. At this time, the liquid layer formed on the entire surface of the substrate is not maintained but is broken. The deionized water supplied onto the substrate W flows locally from the center of the substrate to the periphery thereof in a streak shape (or in a stream shape). Then, the nozzle is moved toward the periphery of the wafer W while supplying the deionized water. At this time, the nozzle is moved while minute water drops are absorbed into the streak-shaped flow of the deionized water, the minute water drops remaining on the surface of the substrate after the liquid layer formed on the entire surface of the wafer W is broken. When the nozzle is moved toward outside the periphery of the substrate, the streak-shaped flow of the deionized water disappears from the surface of the substrate, and the surface of the wafer W is dried.